During a minimally invasive deployment of a mitral valvuloplasty device into the coronary sinus near realtime tracking of the device is monitored to determine whether the device is compressing the left circumflex coronary artery or is likely to do so. In one embodiment of the invention, one or more position sensors are included in the catheter that is used to deploy the constricting implant and or in the implant itself. The position of the device is determined during deployment, and compared to the location of the left circumflex coronary artery, which may be determined by mapping relative to a pre-acquired image or by simultaneous intracardiac ultrasound imaging.